After months of watching contestants battle on NBC's 15th season of The Biggest Loser, we finally found out which biggest loser would be the biggest winner, collecting the $250,000 grand prize during Tuesday night's finale weigh-in. Though finalists Bobby Salem, David Brown and Rachel Frederickson certainly put in effort, former competitive swimmer Frederickson walked away the biggest loser. Her win was not unexpected — her competitive spirit took center stage through most of the season, but it's that spirit that may have led her to lose what some are declaring a shocking amount of weight.

Frederickson, who is 5'4," took the stage at the finale weigh-in at 105 pounds, marking a total weight loss of 155 pounds. While it was enough of a loss to win the entire competition over Salem and Brown (uplifting, considering women rarely win the series), it was also enough of a loss to put her final weight at a BMI of 18, which, according to the BMI scale, is underweight. "I was shocked," Nicole Michalik, former Biggest Loser Season 4 contestant tells Bustle. "It made me sad and she looked sad."

Immediately upon winning, Frederickson and NBC faced backlash for the winner's appearance on social media. Viewers took to Twitter and Facebook with their outcries of concern for Federickson and disappointment in NBC for allowing a contestant to shrink to an underweight BMI. But no one appeared more surprised watching the finale than some of the coaches themselves: A screengrab of Bob Harper and Jillian Michaels' open-mouthed reactions spread on social media Wednesday morning. "I think they probably saw her before, but I do think they were shocked," Michalik says. "They like drastic weight loss, but they still want the show to have a positive reputation." And, based on the social outcry following the Frederickson's win, The Biggest Loser's reputation for encouraging overweight contestants to lose weight healthily could suffer after this season.

One way the show can remedy the brewing controversy is by changing the overall goal for winning the show. Currently, the contestants can win the $250,000 grand prize by losing the largest percentage of weight of any of the contestants. The problem with this method is that it turns weight loss into an extreme competition and gives an unfair advantage to contestants who enter the competition with more weight to lose.

Frederickson began the competition at 260 pounds, which was considerably less weight to lose than her fellow competitors, Salem and Brown, who initially weighed in at 358 and 409 respectively. Therefore, the men had the edge to win because they logistically had more pounds to shed. The result of it all? A winner who pushed herself to the brink to lose every pound possible to win the cash. "Just by watching her this season, you could tell how frail she was," Michalik says. "Her getting hammered by the media [today] is going to make it that much worse."

As we well know, contestants and even winners who have appeared on The Biggest Loser have suffered rocky futures after starring on the show. As Michalik says, "The irony of the show is that it's called a reality show, but it's anything but reality. Your life literally stops for eight months so you can just lose weight. When two, three, four years set in after the show, and real life resumes, it's hard for a lot of people." Add onto that thousands of people who have taken to Twitter to tell a formerly overweight woman that she looks bad skinny too, and it's easy to sympathize with whatever is in Frederickson's future after her weigh-in.

While it's clear the The Biggest Loser is in need of some major improvements — including, suggests Michalik, a heavier focus on therapy as an element of weight loss — NBC has yet to issue comment about the controversy. And some feel it should — after all, the last thing the already struggling network needs is a seres that could encourage unhealthy weight loss in front of an American audience with a growing obesity epidemic.